I suppose by that logic that Reuven would consider it Lashon Hara to say, “Shimon voted for John McCain.”
Not quite. It’s not up to Reuven. The fact is that you are pointing out his being different than you and the Mekabel and making him appear weird to the crowd. If he yells about Shimon, that will only make himself sound odd.
Now to nfgo’s OP, I really don’t think calling the guy an idiot for having done something is the LH. If anything, he is arguing on that opinion. But still, the LH would be to announce that Reuven voted for BOH, especially to a crowd who can relate to ‘he’s such an idiot’ for having done so.
As to if I’m trolling, I can’t tell. That term went through many generations of definitions here in the CR (and was the basis of most CR LH). I lost track of all of them. You probably meant to ask if I’m kidding, but if you can’t tell you don’t deserve an answer.?